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1953-54 Theatre Catalog, 11th Edition, Page 250 (214)

1953-54 Theatre Catalog, 11th Edition
1953-54 Theatre Catalog
1953-54 Theatre Catalog, 11th Edition, Page 250
Page 250

1953-54 Theatre Catalog, 11th Edition, Page 250

BURNER MECHANISM on the Strong 90.0004 arc lump designed for 3-D projection is shown here.

picture to the right eye of the audience; and the left-eye image to the left eye.

There are only two places where the selection of the correct right- and lefteye images can occur: at the screen and at the spectators eyes.

The obstacles to practical direct-vision 3-D screens-that is, without polarizing spectacles-are unbelievably formidable. As one engineer expressed it: "Show me

COMMENT ON S-D is typified in this cartoon by Ben Whitman. in the Stockton California Record.


six workable perpetual motion machines and P11 show you one 3-D process that doesnt require glassesfl He has a long time to make good on his promise.

The most satisfactory method yet devised is selection at the patron's eyes, using polarizers and viewers.

Unfortunately there are serious light losses. The polarizing filter at the boothport blocks 50 per cent of the light trying to pass through it. Surface losses and absorption account for another 10 per cent. The actual light loss between the projectors and the eyes of the audience runs as high as 70 per cent. To make up for this loss, the light output from each of the two necessary projectors would have to be increased by a factor of 2.5.

All of the present stereo pictures are 2-film shows, which means that two projector lamps will be burning at the same time. Your lamp supply facilities must be able to carry this load for an hour of continuous running. If they canlt, you will need another generator or rectiner.

3-D Conversion

To convert to 3-D, you will require: A mechanical or electrical interlock so your projectors will operate in perfect synchronization.

-by Whitman

You must have a metallized-surface perforated projection sceen. Beaded and white matte screens destroy the stereo effect by depolarizing the light.

You will need larger reels and magazines. The stereo standards committee recommends 25-inch magazines,to accommodate 24-inch reels. These permit a 10-thousand foot show with only one intermission.

You will also require two porthole frames for holding the two polarizing filters. A small fan, trained on each of the filters, will prevent overheating and buckling. Filters are cleaned with a static-master or similar brush. Two extra filters should be carried as spares.

And, of course, you will need an adequate supply of viewing spectacles.

Target test films are necessary to align the two projectors. Their horizontal and vertical centers must be superposed on

the screen.

For Warnerls uHouse of Wax," and some other 3-D films, you will need a stereophonic sound system.

In projection, as in cinematography, a very high order of precision is essential to realize and maintain the stereo effect.

Your two interlocked machines project the twin images from the two films so they are superposed on the screen. An out-of-sync error of one frame is enough to be noticeable and irritating. Framing of both images must be identical, as vertical differences set up eye-strain. The light output from each projector must be equal. Any falling-off of screen quality in one or both images weakens the stereo impression. Projection lens must be closely matched for distortion and focal length.

Unlike the presentation of conventional pictures, anything less than fine projection destroys what you are selling-a three-diemnsional motion picture. Donlt go in for 3-D unless you can do a top-notch job of projection!

One thing about the present 3-D techniques disturbs many showmen and engineers. It is reversing the steady trend toward higher levels of screen brightness and doing away with the black-framed screen.

The stereo impression is best obtained by viewing the moving images through a itstereo windowfl This so-called window is smaller than the screen frame, and appears even smaller than it is, particularly when the scene is shot with too widely separated camera lenses.

Some observers believe that the current fate of 3-D will hinge on the publicls reaction to the first three stereo films made by the major studios. These are Warner's fiHouse of Wax," Columbia's "Fort Ti," and Paramountls uSangaree."


()ne of the loudest battle cries since the War is uStandardization."

Standardization means, however, three different things to as many different groups of people.

To mm populous segment of the in .dustry it means freezing new develop ments at a point where they will cost the [0(th money. They see improved methods from the standpoint of costinstead of benefits,

The second group wants and expects all producers to agree on a single

1953-54 Theatre Catalog, 11th Edition, Page 250